"Nanocomposites and nanomaterials"

The Effect of Pressure on Palladium Hydride Nanopartciles formation by Supercritical Carbondioxide Deposition Method
Bilgehan Güzel1, Fatma Ulusal1, Burcu Tezcan1, Saliha Baran1 

1 Chemistry Departmant, University of Cukurova, 01330 Adana, Turkey
bilgehan@cu.edu.tr

The studies about the interaction of transition metal atoms with H2 have gained importance in the last 40 years. Palladium metal is one of these materials which the presence of palladium hydride (PdHx) within these materials increases the catalytic activity and affects the magnetic, electronic, conductivity and hydrogen storage properties [1-2]. There are many methods such as laser ablation of the bulk target material in liquids, electrochemical and in high-pressure gaseous hydrogen condition methods for preparing the palladium hydride nanoparticle. The hydrogen gas pressure was determined to be 12 kbar at 25 °C in previous studies to prepare the PdH nanoparticles at a 1:1 (Pd/H) ratio [1] .

Figure 1. Preparation of PdHx nanoparticles by scCO2 deposition method

In this study, the preparation of multiwalled carbon nanotube supported palladium hydride using a novel precursor, 4-perfluoro-vic-dioximato palladium(II) (Pd(4PFVD)2), using a supercritical carbon dioxide deposition method is reported. The effect of pressure variation at constant temperature on the crystal lattice and PdHx amount are investigated. PdHx/MWCNT nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD).  Prepared PdHx/MWCNT nanocatalyst was used as catalyst for cross-coupling reaction of bromobenzene and phenylboronic acid. 
1.	Tripodi P., McKubre M.C.H., Tanzella F.L., Honnor P.A., Di Gioacchino D., Celani F., Violante V., Temperature coefficient of resistivity at compositions approaching PdH, Phys. Lett. A-2000,-276, 122-126.
2.	Caputo R., Alavi A., Where do the H atoms reside in PdH, systems?, Mol. Phys., -2003,-101, 1781-1787.